Electrically heated sauna bath unit

ABSTRACT

An electrically heated sauna bath unit has a plurality of electrical heating elements in the form of a flattened helix surrounded by a jacket which defines therewith an air passage through which air heated by the elements flows. The elements define a space forming a substantially vertical column for accomodating a mass of stone material which accumulates heat against a time when water is thrown thereon. The column has a length which is at least twice its width and a width which is about four times the average size of the stone constituting the stone material. In one embodiment the stone material is in direct contact with the heating elements and is divided by vertical plates secured to the elements and extending the full height of the column. In a second embodiment, the stone material is accomodated in a magazine for indirect heating by the elements.

United States Patent 191 Torvfelt ELECTRICALLY HEATED SAUNA BATH UNIT [75] Inventor: Nils Allan Emanuel Torvfelt,

' Enkoping, Sweden [73] Assignee: AB Bahco Ventilation, Enkoping,

Sweden [22] Filed: Nov. 2, 1971 21 Appl. No.: 194,977

[30] Foreign Application Priority Data Nov. 3, 1970 Sweden 14848/70 [52] .U.S. Cl..... 219/365, 4/160, 122/40, 126/344, 219/275, 219/362, 219/530 [51] Int. Cl. '..'H05b l/00, A6lh 37/00 [58] Field of Search 219/362, 365-368, 219/378,.530, 540, 271-276, 374-376;

[56] References Cited UNITED STATES PATENTS 3,476,913 11/1969 Bcrve et al 219/365 3,372,264 3/19 8 Williams ..'219/365 X 3,530,277 9/1970 Kujamsuu 219/365 FOREIGN PATENTS OR APPLICATIONS Canada.-. 219/365 1111 3,786,231 1451 Jan. 15, 1974 814,548 6/1969 Canada ..2l9/365 Primary ExaminerA. Bartis Attorney-Harold J. Birch et a1.

[5 7 ABSTRACT An electrically heated sauna bath unit has a plurality of electrical heating elements in the form of a flattened helix surrounded by a jacket which defines therewith an air passage through which air heated by the elements flows. The elements define a space forming a substantially vertical column for accomodating a mass of stone material which accumulates heat against a time when water is thrown thereon. The column has a length which is at least twice its width and a width which is about four times the average size of the stone constituting the stone material. ln'one embodiment the stone material is in direct contact with the heating elements and is divided by vertical plates secured to the elements and extending the full height of the column. In a second embodiment, the stone material is accomodated in a magazine for indirect heating by the elements.

4 Claims, 3 Drawing Figures 1 ELECTRICALLY HEATED SAUNA BATH UNIT The present invention relates to an arrangement in I electrical sauna bath units provided with electrical heating elements encapsulated in tubes as a source of heat for heating air passing through the unit, the electrical elements being arranged to encircle a magazine accomodating stones for accumulating heat, on which stones can be poured when desired to increase the humidity of the bath atmosphere.

Withpreviously known units of this type, the magazine accomodating the stones is, for example, circular or square in horizontal cross section, i.e., the width of the space is equal to its depth. Any deviation from this construction of previously known units will only afford insignificant differences in measurement in the two mentioned directions. It is, however, in certain cases desirable to be able to transfer a substantial portion of the heat from the electrical elements to the stones so that the stones are able to provide an effective steam atmsophere shortly after starting up the unit and at short intervals thereafter. Even if the electrical elements are placed in direct contact with the stones around the periphery of the space in which they are accomodatecl, the transfer of heat to the stones in the interior of the space is restricted by the heat transfer between the stones and the heat transport distance as well as the size of the stones is important to the transportof heat to the interior of the stones. The previously known construction of the stone magazine having substantially equal depth and breadth when seen in cross section and with the magazine used for storing relatively large stones therefore provides no satisfactory solution to the problem of rapidly heating the stones.

The object of the present invention is to provide an improvement in this respect when using simple and inexpensive means. This object is'achieved by means of.

the arrangement of the present invention which is mainly characterized in that the electrical elements are arranged in the form of a flat helix so as to form a sub stantially vertical column for receiving the stones, the cross section of the column having a length which is at least twice the breadth of the column.

Owing to the fact that the electrical elements of the illustrated arrangement are in the form of a flattened helix a more favourable relationship is obtained between the defining surfaces and the volume of the space accomodating the stones. Thus, a larger portion of the stones are in direct equal contact with the electrical elements or with a heat transferring wall of the magazine arranged along the elements. At the same time as a large number of stones is thus heated directly and uniformly, a small number of stones is heated indirectly via the first mentioned stones and no stones need be located at excessive distances from the source of heat, as with previously known arrangements. Thus in respect of the stones unfavourably placed the distance travelled by the heat is shorter. To provide for an advantageous relationship betweenthe heat transport between the stones and the transport of heat within the stones, the smaller cross sectional measurement of the column is suitably of the order of four times the average size of the stones.

The invention will now be described in more detail with reference with an embodiment thereof illustrated in the accompanying drawings, which 2 FIG. 1 is a horizontal sectional view along line B-,-B through a sauna bath unit and FIG. 2 is a vertical section along line A-A in slightly larger scale through the same unit.

F IG. 3, is a horizontal sectional view of a fragmentary v portion of FIG. 1.

The illustrated unit comprises a casing or jacket 1 provided with suspension means by means of which the unit can be mounted to a wall or the like, coupling means for the electrical elements 2 and for supporting other components known'with conventional units. The electrical elements 2 are arranged to encircle a collection of stones 3, i.e., the mentioned so-called stone magazine.

The electrical elements 2 are arranged in the form of a flattened helix in a manner to form a substantially vertical column for directly receiving the stones 3, which are of substantially equal size, the cross section of the column having a width B which is of the order of four times the average size of the stones, and a length L which is of the order of at least twice the width B.

For the purpose of further improving the transportation of heat inwardly and at the same time support the loops of electrical elements, the column is divided in its longitudinal direction into a number of compartments by means of plates 4 provided along their vertical edge surfaces with slots 5 for receiving the elements 2, said plates also forming secondary heat exchange surfaces.

If the unit is to be provided with means for continuously vaporizing water, to increase the humidity in the sauna bath to a certain basic. level, in addition to the increase in humidity obtained when pouring water on to the stones, the means are suitablyin the form of a water container 6 shown in FIG. 1 located at one short end of the column. To enable the supply of heat to be adjusted, the water container may be provided witha displaceable layer of insulating material 7 or may itself be movable. I

The illustrated embodiment is also provided with a bottom portion 8 which is stationary relative to the casing 1 and which is arranged to support the plates 4 bearing against the under edge surfaces thereof, and to take up the load from the stone magazine resting thereupon. Located beneath the bottom portion 8 is a plate 9 which serves as a radiation shield against the floor of the steam bath room and for collecting water spillage. With a sufficient number of plates 4 arranged along the electrical elements 2, as opposed to what is otherwise normal, it is generally unnecessary, to arrange radiation restricting shields on the inside of the casing walls to reduce the surface temperature on the outside of the walls.

In an alternative embodiment, as shown in FIG. 3, the stones may be accommodated within a stone magazine 10 placed within the heating elements 2.

The invention is not restricted to the illustrated and described embodiment but can be modified within the scope of the accompany claims.

I claim:

1. An electrically operated sauna bath for heating stone material or the like comprising a jacket, electrical heating elements in the form of a flattened helix, said jacket surrounding said heating elements and defining therewith an air passage, the air flowing through said passage being heated by said elements, said elements defining a flattened helical space forming a substantially vertical column for accommodating said stone material which accumulates heat against a time when water is thrown thereon, and a support plate means for supporting said stone material in said column, said column having a cross-sectional configuration with a length which is at least twice its width, the width of said column being preferably about four times the average size of the stones constituting saidstone material received thereon.

2. A sauna bath as claimed in claim 1 further including a plurality of vertically oriented plates arranged perpendicular to the longitudinal axis of the column dividing said column into a number of compartments, each of said plates having slots along the vertical edges 7 support plate.

4. A sauna bath as claimed in claim 1 including a magazine for accommodating said stone material, said magazine being located within the flattened helical space defined by said heating elements and surrounded by said heating elements. 

1. An electrically operated sauna bath for heating stone material or the like comprising a jacket, electrical heating elemeNts in the form of a flattened helix, said jacket surrounding said heating elements and defining therewith an air passage, the air flowing through said passage being heated by said elements, said elements defining a space forming a substantially vertical column for accommodating said stone material which accumulates heat against a time when water is thrown thereon, and a support plate means for supporting said stone material in said column, said column having a crosssectional configuration with a length which is at least twice its width, the width of said column being preferably about four times the average size of the stones constituting said stone material.
 2. A sauna bath as claimed in claim 1 further including a plurality of vertically oriented plates arranged perpendicular to the longitudinal axis of the column dividing said column into a number of compartments, each of said plates having slots along the vertical edges thereof for receiving said electrical heating elements, said plates comprising means for conducting heat from said heating elements to said stone material.
 3. A sauna bath as claimed in claim 2 wherein said vertically oriented plates also rest supportably on said support plate.
 4. A sauna bath as claimed in claim 1 including a magazine for accommodating said stone material, said magazine being located within the flattened helical space defined by said heating elements and surrounded by said heating elements. 